Somogyi rebound
Somogyi rebound aka "Somogyi's phenomenon" is a common phenomenon in pet diabetes, probably more common than in humans. When blood sugar levels drop too far or too fast, the animal will defensively dump stored glucose from the liver into their bloodstream, resulting in high blood sugar. It was first documented by a Dr. Somogyi in 1938 as Hypoglycemia-induced Hyperglycemia http://www.petdiabetes.org/somogyi.htm. What you'll see It's confusing but true: Too little insulin means pre-shots are too high; too much insulin often also means pre-shots are too high. This effect is often noted by those who test their pets' blood glucose at home. It means that even when blood glucose levels are too high, simply raising insulin dosage can make things worse instead of better. What's going on The reason: Anytime the glucose level drops too far or too fast, the cat or dog may defensively dump glucose into the blood by breaking down glycogen from the liver. Hormones epinephrine and cortisol, causing temporary insulin-resistance, will also be released into the bloodstream. (If these are insufficient, hypoglycemia ensues!) (See this nice tutorial on the insulin/glucagon equilibrium) Even when raising the insulin dose slowly and carefully, it's possible to pass the correct dose and go on to an overdose. (A typical case is increasing bidaily dosage from 1 unit to 2, passing a correct dose of 1.5 units.) This may produce a rebound -- a swift jump in blood glucose up from a dangerously low reading, to beyond the previous pre-shot level. The pet may be a bit less responsive to the same dose the next shot, from those other hormones. Repeating the overdose on subsequent days, and checking only pre-shot readings or urine glucose, can give the dangerously wrong impression that more insulin is needed! Remember to check occasionally at the expected nadir (low point) as well. Repeated overdose with long-acting insulins can even cause high, flat numbers all day long. What if you don't stop it? It's unusual to be monitoring glucose right when this happens, and typical to just continue the overdose, leading to a repeated rebound situation. So it's good to learn to recognize the patterns of repeated rebound. * A typical rebound pattern, most often seen with long-acting insulins, is a high, flat, unresponsive blood sugar over a period of days. Sometimes, often when raising dosage, this high flat curve will be punctuated by sudden drops to very low values, (with possible hypoglycemic events) followed by a fast return to high unresponsive numbers. (It's the sudden dip that distinguishes this pattern from inadequate insulin!) * When using shorter-acting insulins, repeated Somogyi rebound may manifest instead as rapidly alternating high and low blood sugar numbers with no apparent logic. The highs and lows will both be exaggerated compared to what you'd see on a smaller dose. When to suspect this It's not always easy to tell a rebound from a regular curve showing insulin action ending normally. One way to tell the difference is to take a curve (repeated tests every 2 hours starting with the insulin shot) and look for the shape of the curve. If the curve is valley-shaped, and gradual, then you are not seeing Somogyi rebound. Other shapes should arouse suspicion. In particular, if the rise after peak action is faster and rises higher than the original pre-insulin level and the original fall in blood sugar, you have good cause to consider rebound. The only sure way to check is to reduce dosage and look for a better-shaped curve. A fairly sure sign: Anytime blood glucose numbers seem higher after dosage is raised, consider the possibility of a somogyi rebound. But other things can cause unexpectedly high blood glucose too, so look for a clear correlation with dosage changes. Real-life Example External Links *Somogyi explained (from petdiabetes) *Somogyi explained (from caninediabetes) *Somogyi Rebound FAQ (from gorbzilla) *Mini-Biography, Michael Somogyi *Insulin vs. Glucagon Category:RegulationCategory:Conditions Category:Terms